LASER BUMPING PROCESS FOR GAAS DEVICES

Laser chemical vapour deposition with an organometallic gold compound was used to deposit gold bumps from the vapour phase, called laser bum ping. Laser bumping is a novel process in microelectronics and packagi ng technologies and can be used for single chip bumping. The laser dep osition of gold bumps was also demonstrated for bonding applications. The laser bumping process is suggested both for flip chip and tape aut omated bond attachment. It is a flexible approach involving a computer controlled laser deposition system. Process equipment for plating and photolithographic tooling is not necessary. Single chip bumping of de vices with reduced pitches and pad sizes is possible. This paper descr ibes our work on a controlled bumping process with respect to bonding applications. GaAs devices were laser bumped and flip chip thermo-comp ression bonded onto test ceramic substrates. (C) 1997 Elsevier Science Ltd.